Heat bonding polyurethane foams

Abstract

A process for producing a laminate or composite structure comprises heat bonding a substrate to a polyurethane foam, wherein the polyurethane foam is produced using at least one natural oil derived polyol as at least a portion of the polyol used in making the polyurethane foam. The resulting laminate or composite structure comprises at least one foam produced from a polyol composition comprising at least one natural oil derived polyol and at least one substrate with the interface between the foam and substrate being that formed by heat bonding. The invention also includes any article comprising such a laminate or composite structure.

The invention claimed is: 
     
       1. A process for producing a laminate or composite structure which comprises heat bonding a substrate comprising polypropylene to a polyurethane foam, wherein the polyurethane foam is produced using (i) at least one natural oil derived polyol in an amount from at least 30 weight percent based on total weight of polyols, (ii) at least one other polyol which is not a natural oil derived polyol and is a polyether polyol of a mixture of propylene oxide and ethylene oxide having an unsaturation less than 0.1 meq/g, wherein the ratio of natural oil derived polyol to not natural oil derived polyol is 1:1, and (iii) a catalyst blend comprising 0.0015 to less than 0.2 pphp at least one amine catalyst and 0.0015 to less than 0.2 pphp of at least one stannous octoate catalyst,
 wherein the at least one natural oil derived polyol has a functionality of at least 3, a hydroxyl number less than 150, and at least 50 percent by weight of the polyol, based on the total weight of the polyol, derived from natural oil, and wherein the at least one natural oil derived polyol is produced by reacting a hydroxymethylated fatty acid methyl ester with at least one poly(ethylene oxide) triol; 
 wherein the polyurethane foam has a density from 27 to 80 kg/m 3 ; 
 wherein the heat bonding is carried out using high frequency radiation at a frequency of at least 20 MHz for 1-5 seconds, and 
 wherein the resulting laminate or composite exhibits at least one of
 (1) a hydrolytic stability determined at 50 percent humidity aged compression set of at least 50, 45 or 35 percent as measured by the procedures of either ISO 1856-80 or DIN 53578, 
 (2) volatile organic compounds or other fumes emitted as measured by the procedures of VDA 278 of at most about any of 400, 300, 250 or 200 mg; 
 (3) fogging as measured by the procedures of DIN 75201/B-92 of at most any of 5, 4, 3, or 2 mg; or 
 (4) bond strength as measured using the procedures of DIN 53357 of at least about any of 0.3 daN, 0.4 daN, 0.5 daN or 0.6 daN. 
 
 
     
     
       2. The process of  claim 1  comprising (a) heating at least a surface of at least one foam produced using at least one natural oil derived polyol to a temperature above the fusion temperature of the foam to form a tacky liquid or semi-liquid layer, and thereafter or at the same time with the heating operation, (b) contacting a substrate with the tacky or liquid surface of the foam. 
     
     
       3. The process of  claim 2  additionally comprising (c) cooling such that a bond forms between the foam and the substrate. 
     
     
       4. The process of  claim 2  wherein there is at least one additional step after contacting the substrate with the tacky surface of holding, maintaining, or clamping the substrate in contact with the tacky surface. 
     
     
       5. The process of  claim 1  wherein the natural oil derived polyol has at least one of the following characteristics: at least one ester group per molecule, a viscosity of at most about 10,000 mPa·s at 21° C., or a combination thereof. 
     
     
       6. The process of  claim 1  wherein the resulting laminate or composite exhibits at least two of
 (1) a hydrolytic stability determined at 50 percent humidity aged compression set of at least 50, 45 or 35 percent as measured by the procedures of either ISO 1856-80 or DIN 53578, 
 (2) volatile organic compounds or other fumes emitted as measured by the procedures of VDA 278 of at most about any of 400, 300, 250 or 200 mg; 
 (3) fogging as measured by the procedures of DIN 75201/B-92 of at most any of 5, 4, 3, or 2 mg; or 
 (4) bond strength as measured using the procedures of DIN 53357 of at least about any of 0.3 daN, 0.4 daN, 0.5 daN or 0.6 daN.